Hayes and Garber - Cucurbit Breeding

156 BREEDING CROP PLANTS
same result when heterozygous as when homozygous. C alone
or with A gives wrinkled petals and reduces the number of seeds
which set per capsule and induces lower viability of seeds. B
prevents the above action of C. B alone or in the presence of
A and C produces blue anthers and brown seeds. When B is
Table XXXIV gives
absent the seeds and anthers are yellow.
the result of one of several similar studies. The tabular
presentation shows how carefully these studies were carried out.
Inheritance of Size Characters. Studies of length of seed were
made with crosses of the wild angustifolium and cultivated
varieties (Tammes) as well as with crosses between cultivated
varieties. Seeds were of intermediate size in FI and segregation
occurred in F 2 . The number of individuals grown was not large
and the parental forms were not always again obtained. From
two to four multiple factors are necessary to explain results.
Length and breadth of petal were also studied. Three forms
were used, a small-petalled white-flowered variety with a petal
breadth of 3.3 mm., the common varieties with a breadth of
7 mm. and an Egyptian cultivated blue-flowered variety with a
mean breadth of petal of 13.4 mm. In the cross between Egyptian
blue and common white the factors for color of flower
and seed and for size of seed were apparently inherited independently.
Breadth of petal ranged from one parent to the
other in F z . Several factors for size of flower were necessary
to explain results. The common blue with a petal breadth
of 7 mm. was crossed with the small-petalled white with an average
breadth of 3.3 mm. In F 2 all blue-flowered segregates agreed in
size with the blue parent and all white-flowered segregates had
small-sized petals. The cross between Egyptian blue and the
small-petalled white gave blue-flowered races with petals of intermediate
size in F\ and segregation for flower color in F 2 . The
blue-flowered segregates gave a larger average breadth of petal
than the white segregates. Three hundred plants of each color
were examined.
TABLE XXXV. CORRELATION BETWEEN COLOR OF COROLLA AND BREADTH
OF PETAL IN THE F2 GENERATIONS OF FLAX CROSSES
RANGE, MM. AVERAGE, MM.
300 blue-flowered plants 5.7-16.2 10.8
300 white-flowered plants 2. 1-10.4 4.6
Parent Egyptian blue 10.5-16.2 13.4
Parent white-flowered 2.1-4.2 3.3